Bowlby and Ainsworth's theoretical and empirical work

According to Bowlby and Ainsworth's theoretical and empirical work, infants come into the world predisposed to attach primarily to one person only, usually the mother. All other attachments are affiliative (or, secondary). As you know, this has been called into question by researchers such as Michael Lamb who looked at paternal attachment. The research on attachment in different cultures, particularly those cultures in which children are cared for by more than one caregiver, also provides evidence to suggest that infants can attach to more than one primary caregiver. Let's have a friendly debate. Please take a stand for or against this issue. Your argument can be: a) conceptual - arguing for or against Bowlby's claim, supported by Ainsworth's research, that infants are ethologically predisposed to have a primary attachment to only one person; b) or empirical - describing affiliative attachments, showing how they are different from primary attachments. Please post a 150-word response on the topic.